These studies are intended to determine the influence of endogenous prostaglandins (PGs) on the skeletal muscle and renal vascular beds and the conditions under which their influence come into play. One series of experiments will involve the pump perfused gracilis muscle and the identification of the PGs generated with time during the expreriment. A second series will analyze the mechanism of the gradual increase in PGE release from the perfused canine kidney in vivo. Another investigation will entail the determination of PGE renal venous content of the conscious rabbit. Experiments on the rabbit will also be carried out to ascertain the influence of the renal innervation on the development of hypertension and renin release in 2-kidney Goldblatt hypertension.